FLASH. Free-Electron Laser in Hamburg Overview and Status of the Standard Electron Beam Diagnostics...

FLASH.Free-Electron

Laserin Hamburg

Overview and Status of the Standard Electron Beam Diagnostics at FLASH

N. Baboi, DESYfor the Diagnostics Team

Nicoleta Baboi | Electron Beam Diagnostics at FLASH | FLASH Seminar | DESY, Hamburg | Nov. 11, 2014 | Slide 2

FLASH.Free-Electron Laser

in HamburgContents

>Overview of standard beam diagnostics in FLASH1 and FLASH2 General characteristics

> Beam monitors Charge Monitors

Position Monitors

Size Monitors

Loss Monitors

Not all monitor types covered by this talk



in HamburgOverview of Electron Beam Diagnostics in FLASH

FLASH1 FLASH2

Charge Toroids 12 5

Dark Current Monitor 1

Faraday Cups 3

BPMs 6 33

Transverse Size

OTR-Screens ~30

Scintillating-Screens 1 7

Wire scanners (MDI) 10

Wire scanners (Zeuthen) 9

Transverse Position

Button-BPMs 26 12

Stripline-BPMs 33 4

Cold Cavity BPMs 6

Cavity BPMs 17

HOM-based monitors 39

Beam Loss BLMs >70 ~55

Cherenkov Fibers 2 1

Beam Halo Monitors 1x4 1x4

Ionization Chambers 4 4



in HamburgGeneral Characteristics

>General Deliver bunch by bunch measurements, with few exceptions

> FLASH1 Most designed for TTF2, for charges of 1nC and higher

Electronics: VME-based, ADCs with 1MHz

> FLASH2 Most designed for the E-XFEL

Make use of synergies given by the similar time lineSome have been designed specially for FLASH(2)

or have a temporary solution Generally based on MTCA-technology

9 MTCA crates for diagnostics installed at FLASH2 Designed for lower charge

N. Baboi, IBIC’14, THIXB1

J. Feldhaus, D. Nölle, EPAC2004, p. 262



in Hamburg

Charge Monitors / Toroids

FLASH1

> All signals go to VME and uTCA-system

3GUN and 10DBC2 have new front-end (amplifier & filter, like in FLASH2)

FLASH2

> Temporary solution Low-gain front-end channel

CAT cables

(E-XFEL type under tests

M. Werner, IBIC’14, WEPF02)

Charge Monitors: Toroids

W

W

W

W

+

+

+ Front-end

Adapter RTM RTM SIS8900

AMC SIS8300

AMP-200ADC peak

ADC base

VME(Fl1)

uTCA (Fl1&2)



in Hamburg

►

Charge Monitors: Toroids (2)

Resolution of charge monitors along FLASH(1) (~ 0.4 nC) o FLASH-type (VME)

o FLASH2-type (MTCA) old amplifier

O FLASH2-type with new amplifier

► Dark current monitor



in HamburgToroid Protection System (TPS)

5 MeV 150 MeV 1250 MeV

Bunch Compressors

450 MeV

Accelerating StructuresRF Stations

LasersRF Gun

Soft X-ray UndulatorssFLASH

FEL Experiments

Photon Diagnostics

Beam Dump

THzFLASH1

FLASH2

TPS 0 TPS 1

TPS 2

A. Hamdi, DIPAC 2007, p. 349

> Temporary solution using 3 TPS modules designed for FLASH

(not yet commissioned)



in HamburgCharge Monitors: Dark Current Monitor

Dark current

Bunch

7DBC2, 32m



in Hamburg

>Designed by INFN

> Some camera-PCs have to be reset/restarted from time to time

>Recently had to readjust 3 stations in DBC2

Difficult due to missing fine adjustment

2 are adjusted only for a magnification of 1

> Emittance tool

Screens at FLASH1

A. Cianchi, EPAC2004, p. 2619

23.09.2014, 13:42



in HamburgScreens at FLASH2

BEAM

Op

tics

Axi

s

> Scintillator based (LYSO:Ce), spatial suppression of COTR

>Optics: Look under 45 deg

Uses “Scheimpflug´s” principle to extend depth of field

> 10 µm resolution required single bunch, streaked

>Demonstrated at FLASH1

200µm thick LYSO Screen (ON-Axis)2 half 200µm thick LYSO Screens (OFF-Axis)

Dot Grid Target(spot Ø .50mm)

C. Wiebers, IBIC2013, WEPF03



in HamburgScreens at FLASH1 (2)

> Fully commissioned

FLASH2

FLASH1

1FL2SEED4

1FL2SEED6 1FL2SEED7

1FL2SEED5



in Hamburg

>One horizontal and one vertical fork, each with 3 wires

Used also for cross-calibration of BPMs

> Tool for profile scans and emittance

Wire Scanners: Zeuthen Type

P. Castro, DIPAC 2005, p. 205



in Hamburg

>One fork placed at 45deg with horizontal, vertical and diagonal wire

Several WS use one detector

Also possible to read signals from BLMs, with some change in the beam profile

Some have some readout/timing problems, now under work

Jddd panels to be updated

Wire Scanners: MDI/CERN Type

M. Werner, DIPAC 2001, p. 139



in Hamburg

> Button BPMs, stripline BPMs, cold cavity BPMs, button BPMs inside undulators

BPMs in FLASH1

~0.35 nC



in HamburgBPMs in FLASH2: Cavity BPMs

>Cavities Dipole + reference resonator

3.3 GHz, low Q (about 70)

17 installed between undulators – 10 mm pipe

No individual tuning

>Readout (PSI) MBU (Modular BPM Unit) with 2 RFFE for 2 cavity BPMs

Up to 4 MBUs connected to 1 DAMC2 interface board

Timing: decoding timing protocol via fiber in MBU

>Resolution requirement 2 mm rms for 0.1-1 nC and within ± 0.5 mm

(1 mm at XFEL, but longer cables at FLASH2)

M. Stadler, IBIC’14, WEPD12

B. Keil, IBIC’14, WEPD11



in Hamburg

> BPMs in FLASH2 Difference between expected and

measured position with Gaussian fit

BPMs in FLASH2: Cavity BPMs: Resolution

> Test BPMs in FLASH1 0.5 mm rms for 0.24 nC bunch charge

and 0.5 mm bunch offset

Resolution of various FLASH1-BPMs (designed for 1 nC)

~0.35 nCpreliminary

D. Lipka, IBIC’14, TUPF07



in Hamburg

BPMs in FLASH2: Cavity BPMs: Charge

>Charge resolution for 100 pC bunch charge < 0.2 pC rms

D. Lipka, IBIC’14, TUPF07



in HamburgBPMs in FLASH2: Button and Stripline BPMs

> Low Charge BPMs (LCBPM) electronics Name chosen in contrast to system designed

for FLASH for charges of 1nC and higher

Designed for FLASH2 (and to be installed in all FLASH)

Button or

Strip-line BPM

Delay ~100ns

Broadband

RF Combiner

RF cable 3/8“

Length < 80m

Signal of horizontal plane, delay line: ~100ns

TYPICAL SIGNALS FROM BUTTON/STRIP-LINE BPM

B. Lorbeer, IBIC’14, TUPF08F. Schmidt-Föhre, IPAC’14, THPME117

S. Vilcins, IBIC’14, TUPF11



in Hamburg

BPMs in FLASH2: Button and Stripline BPMs: LCBPM

Rear Transition Module (RTM)

180mmx162mm

Compatible with the MTCA.4

for physics standard

RF Front-EndMicroTCA crate

X-ChannelY-Channel100ns

Crate used for the tests includes:• management carrier hub (MCH)• hard disk (HD), processor (CPU) • Digitizer SIS8300• timing module x2timer

RTM Analog Output Signals

G=38dB

Att.>60dB

Peak Detector

5 BPMs/crate

Front Side

Back Side



in Hamburg

BPMs in FLASH2: Button &Stripline BPMs: Operation

RMS at q=36 pC, 200 pulses (incl. beam jitter)

Server Panel for Firmware Adjustment

BPM Expert Panel

Strip-Line BPM Button BPM

sy = 22 mm sy = 39 mm

bunch charge 0.1-1 nC

bunch spacing ≥222 ns

maximum macro-pulse repetition rate 25 Hz

beam pipe diameter 40.5 mm

single bunch resolution 50 μm

Averaged RMS resolution over 1000 bunches of identical train 10 μm

Range for max. resolution +/- 3 mm

Operation range with reasonable signal +/-10 mm

Requirements (from XFEL requirements)



in HamburgHOM-based Position Monitors

>Monitor dipole, beam position correlated, signals excited in the accelerating cavities

Amplitude shows the beam alignment in the cavities, which influences the (transverse) beam quality

Available in ACC1 (3 cavities), ACC39 and ACC2-5

Display only signal envelope



in HamburgBeam Loss Monitors in FLASH1

Cannot distinguish between losses from FLASH1 and FLASH2 pulses



in HamburgBeam Loss Monitors in FLASH2

>Detector Scintillator or fused silica

(rod or fiber)

PMT: HV voltage (~500 V) generated by Cockcroft-Walton multiplier on board mounted at PMT

Scintillators and mechanics built by IHEP, Protvino (60 for FLASH2)

> Electronics MTCA-based with low latency interface with MPS

> Alarms algorithms Single bunch

Multi-bunch

Integration

OR of comparator and FPGA alarms

Readout Electronics

Power control

PMT& HV

Scintillator

Beam Loss Monitor

e,γ,n0

Alarm (to MPS)

A. Kaukher, BIW 2012, p. 35



in HamburgBeam Loss Monitors in FLASH2: Status

>Calibrated single and multi-bunch alarm

> Integration alarms to be calibrated



in Hamburg

Dump Loss Monitors in FLASH1 & FLASH2: BLMs and Ionization Chambers

> BLMs based on quarz-fiber + Ionization Chambers (air filled cables) along last 2m of beam line

> VME/uTCA electronics

beam

FLASH1

N. Baboi, BIW 2010, p. 420



in Hamburg

Dump Loss Monitors: Beam Halo Monitors (FLASH1 & FLASH2)

> Installed behind dump vacuum window 8 sensors: 4 Diamond + 4 Sapphire

> VME-based in FLASH1

> uTCA-based in FLASH2 Basically same electronics and

firmware as FLASH2 BLMs

Under commissioning

FLASH1

A. Ignatenko, IPAC 2012, p. 816



in HamburgAcknowledgement

>Many people contributed to the work and this talk R. Neumann, D. Lipka, N. Wentowski, Z. Pisarov, M. Werner, J. Lund-Nielsen,

B. Lorbeer, A. Kaukher, T. Wamsat, A. Ignatenko, F. Schmidt-Föhre, K. Honkavaara, H. Tiessen, B. Michalek, R. Zahn, B. Keil, D. Nölle, O. Hensler, G. Marinkovic, K. Knaack, J. Schwarz, J. Liebing, H. Sokolinski, G. Kube, C. Wiebers, M. Felber, R. Zahn, S. Vilcins, J. Kruse, D. Renner, M. Felber, S. Schreiber, M. Holz, M. Pelzer, A. Ziegler, M. Hoeptner, H. Sokolinski, M. Stadler, M. Wendt, I. Krouptchenkovand many others

Thank you !



in HamburgOther Electron Beam Monitors in FLASH2

> Loss monitors Cherenkov fibers along undulators (not for XFEL)

> Beam Compression Monitors

> Beam Arrival Monitors

>Coherent Transition Radiation monitors

C. Behrens, IPAC’10, p.912

A. Angelowski, IBIC’14, MOPD25

S. Wesch, BIW 2012, THAP01

Date post:	25-Dec-2015
Category:	Documents
Upload:	andrew-holt
View:	219 times
Download:	0 times

FLASH. Free-Electron Laser in Hamburg Overview and Status of the Standard Electron Beam Diagnostics...

Documents